Bring a large pot of lightly salted water to a boil. Cook the fusilli at a boil until tender yet firm to the bite, about 12 minutes; drain. Drizzle 1 tablespoon olive oil into drained pasta; stir to coat.
Bring a saucepan of lightly salted water to a boil. Cook the fiddlehead ferns at a boil until tender, 3 to 5 minutes; drain. Rinse the fiddleheads in cold water to stop from further cooking; drain.
Cook bacon in a large, deep skillet over medium-high heat until crisp, about 10 minutes. Drain on a paper towel-lined plate. Crumble the bacon once cool enough to handle.
Toss the pasta, fiddlehead ferns, crumbled bacon, and cucumber together in a large bowl.
Combine sun-dried tomatoes, egg yolk, Dijon mustard, lemon juice, and garlic in a bowl. Stream about 1/3 of the vegetable oil into the mixture while whisking vigorously until the mixture begins to emulsify. Stream the remainder of the olive oil into the dressing while whisking; season with salt and pepper.
Pour the dressing onto the pasta mixture; stir to coat.
This recipe contains raw eggs. We recommend that pregnant women, young children, the elderly, and the infirm do not consume raw eggs. Learn more about egg safety from our article, Making Your Eggs Safe.
Making Your Eggs Safe